Water Tank Level Sensing Upgrade

I Recently upgraded my WaterTank Housing and thought it would be good to some how upgrade my water level sensing…Im currently using my own pcb designed around a pic micro i sourced from another Company (10 year ago)…Its worked quite well ,have had to rewire the probes only once in that period…I also use one of these boards to monitor water level in my drain…Anyway i came across AquaPlumb at the Vegetronix website and decided to purchase one…Problem was i dont have anything at the Water Tank that reads analog…I would have liked to get the Water Tank level directly into my Homevision Controller and having recently purchased some I2C range extenders that one of the guys mentioned on the discord channel , i decided to make an analog pcb using ther PCF8591 chip…So heres some pics of what i have currently…

Some pics of my new boards ,4 way analog board ,4 way relay board

…This next pic shows the following , the I2C BUS Extender board (bottom left) above that is another new board which gets the I2C signals into my Homevision Bus…next my Home vision i/o Expanders (input ,output),to the right the new 4 channel analog board… …I have updated the analog board so that it can have 5v ref or 3v3…new boards arrived today…I have the relay boad working starting / stopping my pump, can read analog signals , just waiting on my Aquaplumb to arrive… More Soon …

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That’s a very nicely wired setup! So neat.

What sort of probe arrangement have you been using up until now? Is it multiple probes that activate at discrete depths, or a linear sensor of some kind, or something else?

Hi Jon
It’s multiple probes (using hose clamps) on a piece of ld conduit (grey)
…Based on a pic flashed for a company whom I purchased the chips from …

im using one of your light sensors for testing :+1:

Ah, interesting, so the resolution is just a matter of how many probes you have. For many purposes that’s plenty: it only takes 10 probes to get 10% resolution. More than that is probable too fine-grained to matter most of the time.

I’m interested to hear how the new senser goes.

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Im hoping it works well as it cost $189:00 Oz…

I am curious to see it as well. I have plans to add a 2000 gallon water tank “farm” to the property and scavenge rain water from the gutters to use for lawn watering in the dryer part of the year… as if the Pacific Northwest really gets… dry. Being able to actively monitor that would be nice as I could shut down the watering system when the level gets low.

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We have just moved into a rural property which is on tank water and this was one of the first things I setup. We have 2 20000L tanks that are linked so same level.

Using home assistant (HA), esphome and an ultrasonic sensor I had three a quick solution together and it is surprisingly accurate. It takes 5 readings over 2min and sends the median value to HA.

Tanks haven’t dropped under 35000L yet so will see how goes long term. I had been looking at pressure sensors which are very accurate but so far this solution would be more than enough for what cost less than $20!


Can see the 2 lots of rain we had where it jumps.


Hi Kerry

Like the idea of charting the tank level , but not keen on bringing a pc into the mix…When looking for level sensing back in 2009 i did investigate using ultrasonics and bought some from Maxbotix…
https://www.maxbotix.com/product-category/lv-maxsonar-ez-products....worked ok but occassionly from memory they gave wonky reading…so used what i currently got…keep us posted on how yours performs . i might still have a play ,since i still have some Maxbotix sensors and it outputs analog…

Hi @Kerry,

Can you give some more details on your ultrasonic sensor? I have been wanting to do this for some time but have been worried about corrosion in damp environments.




Time will tell as to how long it lasts but I did use it a year or so ago in a drain for notifications when likely to flood, still working fine now so pretty confident it decent enough… and for $5 no issues if have to replace every now and then.

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Well my Aquaplumb arrrived today ,so i put my rain sensor install aside and started on the Aquaplumb install…I quickly removed the strainer on the watertank tied the sensing lead to a piece of HD 20mm conduit i had lying around…Connected it to the waterTank analog board and went through the calibration process…Checked my reading on my Homevision screen and it showed 155…ummm bit low i thought…Remembered i needed to install my latest analog board which allows 3v ref as the Aquaplumb puts out 3v max…Replace analog sensor board and reconnected the aquaplumb…re calibrated sensor and checked the reading again 227…That,s better…My tank wasn,t full so i topped it up and it changed to 231…Tank FULL…checked the voltage output of the sensor …2.996v…ummm should have at least 250…?..Then realised i was using a 3.3v ref …So it looks ok for now…At the moment i check the sensors every 10 seconds,and every 15minutes i check and see if the value is greater than 230 if so turn a relay on out at my water tank I2C Expander relay…some pics of the Aquaplumb install…

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It sounds like you have a winner :slight_smile:

Thanks for the update.

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I hope so…time will tell …

But sometimes you just need to go back to the old ANALOG technology to get things done. My ultrasonic distance sensors failed and I needed to get the rain barrel watering system (drip watering system) up and running. So I re-installed the original rain barrel electronics that I used 10 years ago. Yes I still had it on a shelf in the shed. It is comprised of a float on a string that is connected to a lever switch that allows power to the submerged waterfall water pump at the bottom of the main rain barrel, when there is enough water in barrels. Nine of the rain barrels are connected to the main rain barrel via a 1" (25mm) PVC pipe. The power is supplied to the switch using an Insteon On/Off module 3 times a day for 10 minutes each. As you are aware, the sun here in Florida is brutal in the summer months.

So how do I monitor the water level. For some reason, I left the original level monitoring system in place from 10 years ago. It is a conversation piece. It is comprised of a long piece of 1/2" (12mm) PVC that I used a threaded end connector and tapped/sealed it into a large mixed nuts plastic container. The container floats on top of the water and as the water level drops so does the PVC pipe. I can see how much it has dropped by my security camera that is pointed in that general direction.
OK, so I received my new waterproof ultrasonic sensor last May and unfortunately my other priorities have pushed this lower down the “Must Do” list. What could be more important… well now the sewer pipe from the house to the city box needs to be replaced and I will be digging up the yard to replace it. I was thinking of adding a camera to the clean-out fitting plug and maybe as someone else mentioned a ultrasonic sensor to measure the water level in the pipe. Will probably be to tired to do that from the 50’ of trenching.